Used car guide

2004 Smart Forfour: common problems and MOT failures

What MOT testers find on the Smart Forfour first registered in 2004: we looked at the 616 MOTs these cars had during 2023–2025. Plus known faults and what to look at before you buy one.

616MOTs of 2004 cars, done in 2023–2025
55%pass first time (all 2004 cars: 57%)
5,400typical miles a year
2.2×the usual rate for track rod ends

What goes wrong more than usual on a 2004 Smart Forfour?

Parts flagged at MOT more often on the 2004 Smart Forfour than on all cars registered in 2004.

  • Track rod ends2.2× usual
    Smart Forfour
    14.1% All 2004 cars
    6.5%

    Failed outright at MOT: 6.7%, against 3% of all 2004 cars. The rest were advisories or minor defects.

    Rough price £50–£150 (one end, plus about £30–£50 if it needs a wheel alignment) ClickMechanic

    At the viewing: On a straight road the steering wheel should sit straight. Listen for knocks when turning, and check the steering feels even.

  • Ball joint dust cover2.2× usual
    Smart Forfour
    10.4% All 2004 cars
    4.7%

    Failed outright at MOT: 2.4%, against 1.8% of all 2004 cars. The rest were advisories or minor defects.

    Rough price £60–£150 (one joint) ClickMechanic

    At the viewing: Listen for knocking over bumps and check the rubber boots behind the wheels aren't split.

Common 2004 Smart Forfour MOT failures and advisories

The share of 2004 Smart Forfour MOT tests where testers flagged each area, as a fail or an advisory. Rough prices are typical independent-garage costs.

  • Lights and electrics
    51% of testsRough price £10–£80

    At the viewing: Ask a friend to check every light, including brake lights and indicators, while you operate them.

  • Suspension
    49% of testsRough price £120–£400

    At the viewing: Listen for knocks over speed bumps, and look behind each front wheel for a snapped coil spring.

  • Brakes
    35% of testsRough price £150–£350

    At the viewing: Look for a lip on the disc edges and feel for judder or pulling when braking firmly from about 40mph.

  • Tyres
    33% of testsRough price £70–£150

    At the viewing: Check the tread on all four tyres, including the inside edges, and look for cracks or bulges.

  • Wipers, windscreen and mirrors
    13% of testsRough price £15–£250

    At the viewing: Check for chips in the driver's view, and test the wipers and washers.

  • Oil and fluid leaks
    10% of testsRough price £80–£600

    At the viewing: Look under the engine and on the ground where the car is usually parked for fresh oil or fluid.

Questions to ask the seller before buying a 2004 Smart Forfour

Ask before you travel to see it. A seller who knows the car will have answers, and receipts.

  1. Any recent work on the track rod ends? (Flagged at MOT 2.2× as often on the 2004 Smart Forfour as on other cars the same age.)
  2. Any recent work on the ball joint dust cover? (Flagged at MOT 2.2× as often on the 2004 Smart Forfour as on other cars the same age.)
  3. Can I see the service history and receipts for any big jobs?

Looking at a Smart Forfour?

Check the actual car: its own MOT history, mileage and what to ask the seller. Free, no sign-up.

Other years

Every year of the Smart Forfour compared

YearMOT testsMost flagged
2022–Too few tests
2021–Too few tests
2020–Too few tests
20195,746Tyres 28%
201811,318Tyres 31%
201714,152Tyres 32%
201615,704Tyres 33%
201516,282Tyres 32%
2007168Lights and electrics 54%
20061,378Lights and electrics 46%
20051,765Lights and electrics 48%

Where this comes from: the DVSA's anonymised results for every MOT test done in Great Britain during 2023–2025, counting the MOTs of Smart Forfour cars first registered in 2004. "Flagged" includes advisories, so it isn't the same as a fail rate. How we score